One of her Twilight costars has revealed that he was actually taken aback when he saw Stewart as a pregnant Bella Swan because, well, it was so realistic...

"There was one time when I got to set and she had some kind of makeup on to make her look...really tired," Jackson Rathbone told us at Teen Vogue's Young Hollywood party at Paramount Studios in Hollywood. "I felt really bad. I was like, 'What happened to her? Is she alright?' She was like, 'Dude, come on. It's makeup.' I was like, 'OK cool, because I was really worried.' Honestly, I was like, she must have had three weekends in Vegas."

Fortunately, the look didn't carry over to the big wedding scene with Edward. "We had to keep telling ourselves it was fake," Rathbone said. "We've been watching this relationship develop and even though we're playing the parts and at the end of the day we wash off that white face makeup and peel back the wigs that we're wearing, when we were there at the wedding scene, all of us felt it. She just walked out, everybody was quiet. Your heart would skip a beat, you get kind of teary-eyed."